RHSA-2026:99758 - Security Advisory

Topic

An update for osbuild-composer is now available for Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On.

Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

A service for building customized OS artifacts, such as VM images and OSTree commits, that uses osbuild under the hood. Besides building images for local usage, it can also upload images directly to cloud. It is compatible with composer-cli and cockpit-composer clients.

Security Fix(es):

• google.golang.org/grpc: gRPC-Go: Denial of Service via malformed RPC requests (CVE-2026-84445)
• net/http: golang: golang: Denial of Service via crafted HTTP Range headers (CVE-2026-78667)
• crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references (CVE-2026-97031)
• net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing (CVE-2026-94440)
• net/http: net/http/internal/http2: golang.org/x/net/http2: net/http: Denial of Service via excessive HTTP/2 SETTINGS frames (CVE-2026-78669)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle Long Life 8.6 x86_64
• Red Hat Enterprise Linux Server - AUS 8.6 x86_64

Fixes

• BZ - 2533175 - CVE-2026-84445 google.golang.org/grpc: gRPC-Go: Denial of Service via malformed RPC requests
• BZ - 2548334 - CVE-2026-78667 net/http: golang: golang: Denial of Service via crafted HTTP Range headers
• BZ - 2548336 - CVE-2026-97031 crypto/tls: golang: crypto/tls: Denial of Service via multiple ECH outer extension references
• BZ - 2548341 - CVE-2026-94440 net/textproto: mime/multipart: golang: golang: Denial of Service via memory limit bypass in multipart form parsing
• BZ - 2548344 - CVE-2026-78669 net/http: net/http/internal/http2: golang.org/x/net/http2: net/http: Denial of Service via excessive HTTP/2 SETTINGS frames

CVEs

• CVE-2026-78667
• CVE-2026-78669
• CVE-2026-84445
• CVE-2026-94440
• CVE-2026-97031

References

• https://access.redhat.com/security/updates/classification/#important